Boat trailer fenders prevent mud, water or debris from splashing or hitting the other vehicles driving on the road. The fenders are located above the tires of the trailer. They are fixed with bolts and nuts. It is easy to access these bolts, in most cases, without lifting the trailer with a jack. However, you can use the jack and lift up the trailer to work, if required.

Step 1: Stopping the Trailer from Rolling

Put the wood blocks against the tries, so that the trailer will not roll. If you have fenders with mounting holes behind the wheel, jack up the trailer. Remove the wheel by removing the lug nuts, using a lug wrench.

Step 2: Removing old Fenders

Remove the existing fenders by removing their nuts and bolts with a wrench. Align the front and backs of old and new fenders by putting them together. Mark the position of holes on the new fenders.

Step 3: Checking the Fender

Check the fit of fender, by holding it against the side of trailer over the wheel. Adjust its length by pushing it or pulling it. You can adjust about ½ inch.

Step 4: Drilling the Holes

Punch the center on the mark. Drill the holes in the fender for fixing bolts.

Step 5: Fixing the Fender

Hold the new fender against the side of trailer with a clamp, to coincide the holes. Fix with bolts and nuts.